I was lucky enough by checking daily new stock of NVIDIA RTX 3090 to get one. As I did not want to build new computer and wanted this card as an eGPU with my 3 years old laptop (Alienware 13), I told myself I am going to try Razer Core X Chroma. The space in it seemed large enough for NVIDIA's card (it has 3 slot wide GPU support) and 500 Watts of GPU support was enough as well (350W). Unfortunately, either due my laptop or new GPU, this set up did not end up working. Even calling Razer's support was not that much help (they didn't know yet if it should work) and so I returned the Razer Core X Chroma and now I am in process of building new PC. (The card fits in though in Razer Core's enclosure - barely but does).
New NVIDIA card is definitely on beefy side (big)
Looking at Sonnet eGFX Breakaway Box 650, 3090 from NVIDIA is not supported either (3070 and 3080 are and some other 3090 from other manufacturers are as well).